Electrodeposition baths are typically supplied as two components: (i) a main vehicle and (ii) a pigment paste. The main vehicle comprises an unpigmented aqueous dispersion which may comprise (a) a main film-forming polymer (e.g., a phosphatized epoxy resin) and (b) additional water-dispersible non-pigmented components. The main vehicle alone may be used as an electrodepositable coating composition if no pigment is desired in the applied coating. However, the electrodepositable coating composition may also comprise both the main vehicle and the pigment paste.
Phosphatized epoxy resins are typically produced in volatile organic solvent. The use of volatile organic solvent is disfavored because of health and environmental considerations. This volatile organic solvent may either be removed by conventional methods, such as vacuum solvent stripping, or will be carried into the dispersions and/or electrodepositable coating compositions that utilize the phosphatized epoxy resin, increasing the amount of volatile organic content present in these compositions.